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1. WO2002034162 - SELECTIVELY THINNED COILED-SHEET STENTS AND METHODS FOR MAKING THEM

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[ EN ]

WHAT IS CLAIMED IS:
1. A stent, comprising:
a generally tubular body having a longitudinal axis and a circumference, and having a size configured for introduction into a body lumen, the tubular body being expandable between a contracted condition for facilitating introduction into a body lumen and an enlarged condition for engaging a wall of a body lumen;
a plurality of cylindrical bands formed in the tubular body, each band comprising a generally zig-zag pattern; and
a plurality of longitudinal connectors extending between and connecting adjacent cylindrical bands, the longitudinal connectors having reduced thickness regions having a thickness t, in a radial direction that is substantially smaller than a thickness t0 of the adjacent cylindrical bands, the longitudinal connectors assuming a generally axial configuration when the tubular body is in its expanded condition.

2. The stent of claim 1 , wherein the thickness t, of the reduced thickness regions is not more than about two thirds the thickness t0 of the cylindrical bands.

3. The stent of claim 1 , wherein the longitudinal connectors are aligned with one another such that the reduced thickness regions define slots extending about the circumference of the tubular body.

4. The stent of claim 1, wherein the generally zig-zag pattern comprises a series of sequential diagonal elements connected to one another and extending about the circumference, the diagonal elements having a generally arcuate shape, all diagonal elements in each band being oriented in either a clockwise or counter-clockwise direction about the circumference.

5. The stent of claim 1, wherein the tubular body comprises a coiled-sheet.

6. The stent of claim 1, wherein the longitudinal connectors are biased to extend substantially parallel to the longitudinal axis when the stent is in the expanded condition.

7. The stent of claim 1 , wherein the tubular body is biased towards the enlarged condition.

8. The stent of claim 7, wherein the generally zig-zag pattern is expandable between an unstretched condition and a stretched condition, the zig-zag pattern being biased towards the stretched condition above a transition temperature which is
substantially below body temperature, thereby at least partially defining the enlarged condition.

9. A stent, comprising:
a generally tubular body having a longitudinal axis, a circumference, and a thickness t0, and having a size configured for introduction into a body lumen;
a plurality of cells formed in the tubular body; and
a plurality of slots formed in the tubular body and oriented substantially perpendicular to the longitudinal axis about the circumference of the tubular body, the slots defining a thickness t, that is substantially less than the thickness t0, the slots configured for enhancing a bending characteristic of the tubular body without substantially permanently deforming regions of the tubular body comprising the slots.

10. The stent of claim 9, further comprising a plurality of connectors extending between and connecting adjacent cells, the connectors being aligned in sets about the circumference of the tubular body, wherein a slot intersects the connectors in each set, thereby providing a reduced thickness region in each connector.

11. The stent of claim 9, wherein the thickness t, of the slots is not more than about two thirds the thickness t.

12. The stent of claim 9, wherein the cells are arranged sequentially about the circumference, thereby defining a plurality of cylindrical bands, and wherein the connectors comprise a plurality of longitudinal connectors extending between adjacent cylindrical bands.

13. The stent of claim 9, wherein the tubular body comprises a coiled-sheet.

14. The stent of claim 9, wherein the tubular body is expandable between a contracted condition for facilitating introduction into a body lumen and an enlarged condition for engaging a wall of a body lumen.

15. The stent of claim 14, wherein the tubular body is biased towards the enlarged condition.

16. A method for fabricating a stent, comprising:
providing a flat sheet of shape memory material including a length, a width, and a thickness t0;
forming a plurality of openings in the sheet to define a multi-cellular structure;
forming a plurality of slots in the sheet aligned substantially perpendicular to the length of the sheet, the slots having a reduced thickness t, that is less than the thickness t0, the slots enhancing a bending characteristic of regions of the tubular body comprising the slots, the shape memory material preventing substantially permanent deformation of the regions comprising the slots; and
rolling the sheet about its length into a tubular body, the tubular body having a diameter configured for introduction into a body lumen.

17. The method of claim 16, wherein the plurality of slots are formed by cutting into the sheet with a saw.

18. The method of claim 16, wherein the thickness t, of the slots is not more than about two thirds the thickness t0.

19. The method of claim 16, wherein the sheet comprises a shape memory alloy and wherein the plurality of slots are formed in the sheet without substantially changing mechanical properties of the shape memory alloy.

20. The method of claim 16, wherein:
the step of forming a plurality of openings in the sheet comprises forming a plurality of cells and longitudinal connectors in the sheet, longitudinally adjacent cells being connected to one another by longitudinal connectors aligned in sets substantially perpendicular to the length of the sheet; and
the step of forming a plurality of slots comprises forming a slot that intersects each set of longitudinal connectors, thereby providing a reduced thickness region in each longitudinal connector.